#include "torch/csrc/jit/script/lexer.h"

#include <c10/util/Exception.h>

#include <string>
#include <unordered_map>
#include <mutex>

namespace torch {
namespace jit {
namespace script {

static const std::unordered_map<int, int> binary_prec = {
    {TK_IF,  1},
    {TK_AND, 2},
    {TK_OR,  2},
    // reserve a level for unary not
    {'<',    4},
    {'>',    4},
    {TK_EQ,  4},
    {TK_LE,  4},
    {TK_GE,  4},
    {TK_NE,  4},
    {'+',    5},
    {'-',    5},
    {'*',    6},
    {'/',    6},
    {'%',    6},
    {'@',    6},
    {TK_POW, 7},
};

static const std::unordered_map<int, int> unary_prec = {
    {TK_NOT, 3},
    {'-',    8},
    {'*',    8},
};

bool SharedParserData::isUnary(int kind, int* prec) {
  auto it = unary_prec.find(kind);
  if (it != unary_prec.end()) {
    *prec = it->second;
    return true;
  }
  return false;
}
bool SharedParserData::isBinary(int kind, int* prec) {
  auto it = binary_prec.find(kind);
  if (it != binary_prec.end()) {
    *prec = it->second;
    return true;
  }
  return false;
}

int stringToKind(std::string str) {
  static std::once_flag init_flag;
  static std::unordered_map<std::string, int> str_to_kind;
  std::call_once(init_flag, []() {
    for (char tok : std::string(valid_single_char_tokens))
      str_to_kind[std::string(1, tok)] = tok;
#define DEFINE_CASE(tok, _, str) \
    if (std::string(str) != "") str_to_kind[str] = tok;
    TC_FORALL_TOKEN_KINDS(DEFINE_CASE)
#undef DEFINE_CASE
  });
  try {
    return str_to_kind.at(str);
  } catch (std::out_of_range& err) {
    throw std::out_of_range("unknown token in stringToKind");
  }
}

std::string kindToString(int kind) {
  if (kind < 256)
    return std::string(1, kind);
  switch (kind) {
#define DEFINE_CASE(tok, str, _) \
  case tok:                      \
    return str;
    TC_FORALL_TOKEN_KINDS(DEFINE_CASE)
#undef DEFINE_CASE
    default:
      throw std::runtime_error("Unknown kind: " + std::to_string(kind));
  }
}

SharedParserData& sharedParserData() {
  static SharedParserData data; // safely handles multi-threaded init
  return data;
}
} // namespace script
} // namespace jit
} // namespace torch
